Lua-Basic-Tutorial

This tutorial follows John Sonmez Youtube tutorial and 游戏大师课 Youtuber tutorial for basics of Lua.

What is the Lua?

Lua is a lightweight, high-level, multi-paradigm programming language designed primarily for embedded use in applications. Lua is cross-platform, since the interpreter of compiled bytecode is writtten in ANSI C, and Lua has a relatively simple C API to embed it into applications.

Lua was originally designed in 1993 as a language for extending software applicationss to meet the increasing demand for customization at the time. It provided the basic facilities of most procedural programming languages, but more complicated or domain-specific features were not included; rather, it included mechanisms for extending the language, allowing programmers to implement such features. As Lua was intended to be a general embeddable extension language, the designers of Lua focused on improving its speed, portability, extensibility, and ease-of-use in development. (from wikipedia)

Types - 8 basic types

• nil
• boolean
• number
• string
• userdata
• function
• thread
• table

Operators

• Arthmetic (+, -, *, /, ^, %)
• Relational (<, >, <=, >=, ==, ~=)
  • Note: not equal ~= in Lua
• Logical (and, not, or)
• Other
  • Concatenation
    • "Hi" .."there"
  • Length
    • #suckers

If, Then, Else

if boolean expresion then
        -- do something
else
        -- do something else
end

Loops

• While - while boolean expression do something end
• Repeat - repeat something until boolean expression
• For (Numberic) - for variable = start, end, step do something end
• For (Generic) - for k, v in iterator do something end

Blocks and Scope

By default, all variables in Lua are globally scoped

Variadic Functions

function countStringLengths(...)
        --do stuff
        a, b, c = ...
end

Tables

Ex. (1): grades = {1, 2, 3}
Ex. (2): grades = {"John" = 89, "Steam" = 90}
Note: the index of tables in Lua starts from 1 not 0

Metamethods

• __index
• __newindex
• Operators
  • __add
  • __sub
  • __mul
  • ...
• __call
• __tostring

Overview of Standard Libraries

• Basic
• Package
• String
• Table
• I/O
• Operating System
• Debug

Keywords

and	break	do	else
elseif	end	false	for
function	if	in	local
nil	not	or	repeat
return	then	true	until
while